Detergents

ABSTRACT

A process for preparing—a cleansing composition having pearlescence, which contains adding an ingredient (B) which has been molten beforehand, or an aqueous liquid in which the molten ingredient (B) is contained, to a suspension of an ingredient (A) and cooling the resultant mixture to cause the ingredient (B) to deposit; and the cleansing composition. The process makes it possible to economically produce cleansing compositions which have pearlescence, excellent in the stability of their pearlants, and superb long-term storage stability under acidic conditions and high-temperature conditions.

FIELD OF THE INVENTION

This invention relates to cleansing compositions having pearlescence anda process for preparing them, and specifically to cleansing compositionswhich are excellent in the stability of their pearlants, are superb inlong-term storage stability under acidic conditions and high-temperatureconditions, are inexpensive, and a production process thereof.

BACKGROUND OF THE INVENTION

Cleansing compositions have been developed with a view to achieving bothan improved cleansing function and providing a mild feel andconditioning effects. As the life style diversifies, however, theconsumers' demand has also been diversified, resulting in the demand foran expanded availability with respect to the external appearance andfunction of cleansing compositions.

Concerning the external appearance of cleansing compositions, theimpartation of a pearly appearance can give a luxurious impression, andthus make consumers feel rich. As to the function of cleansingcompositions, there is a demand not only for cleansing performance butalso for a wide variety of functions such as the impartation of a silkyfeel, manageability, combing ease and the like to the hair in the caseof hair cleansing compositions, for example.

To impart a pearly appearance, the use of alkylene glycol mono- ordialkylates has been known conventionally. They, however, have such abroad distribution in their alkyl chain length due to their rawmaterials that an intended pearly appearance can hardly be achieved. Forthe impartation of a silky feel, manageability, combing ease and thelike, it is known to make the pH of a cleansing composition acidic. Theacidification of the pH of the composition, however, involves problemsthat its pearlant in the form of an ester undergoes decomposition andthe stability of the composition is considerably deteriorated,specifically, the composition loses its uniformity and its pearlyappearance is impaired.

DISCLOSURE OF THE INVENTION

This invention provides a process for preparing a cleansing compositionhaving pearlescence and also the cleansing composition. The processcontains mixing an aqueous liquid in which the following ingredient (A)is suspended with the following ingredient (B) which has been moltenbeforehand, or an aqueous liquid in which the molten ingredient (B) iscontained, and cooling the resultant mixture to cause the ingredient (B)to deposit:

-   -   Ingredient (A): an ester ingredient consisting of an ethylene        glycol monoalkylate or ethylene glycol dialkylate which may have        a distribution in the number of carbon atoms in its constituent        fatty acid with a proviso that fatty acids having carbon numbers        of 18 and greater account for less than 70 wt. % of all        constituent fatty acids; and    -   Ingredient (B): an ester ingredient consisting of an ethylene        glycol monoalkylate or ethylene glycol dialkylate which may have        a distribution in the number of carbon atoms in its constituent        fatty acid with a proviso that fatty acids having carbon numbers        of 18 and greater account for 70 wt. % or more of all        constituent fatty acids.

BEST MODES FOR CARRYING OUT THE INVENTION

This invention relates to a cleansing composition which is acidic, isexcellent in the stability of its pearlant and has pearlescence, andalso to a process thereof.

The present inventors have found that a cleansing composition, which hasa superb external appearance and is excellent in the stability of itspearlant under acidic condition, can be economically produced by using acommonly-used pearlant in combination with an ethylene glycol alkylatewhose distributions in the number of carbon atoms of its constituentfatty acids fall within a specific range, and by causing crystals of thelatter to deposit in a system in which crystals of the former aresuspended.

Ingredients (A) and (B) useful as pearlants in the present invention areboth ethylene glycol monoalkylates or ethylene glycol dialkylates.Ingredient (A) is a pearlant which is widely marketed and used.Ingredient (B), on the other hand, is characterized in that thepercentage of ester-constituting fatty acids having greater carbonnumbers is higher compared with general pearlants.

For ingredient (B), fatty acids having carbon numbers of 18 and greateraccount for 70 wt. % or more of all constituent fatty acids, with 80 wt.% or more being preferred from the standpoint of stability under acidiccondition. The carbon numbers of the fatty acids which account for 70wt. % or more of all the constituent fatty acids can preferably fallwithin a range of from 18 to 22. Further, the distribution in the numberof carbon atoms in all the fatty acids can preferably fall within arange of from 11 to 22.

When fatty acids having 18 and greater carbon numbers account for 70 to85 wt. % of all the fatty acids in the combination of ingredients (A)and (B), the resulting cleansing composition is provided with excellentlathering ability, pearly appearance and stability.

The content of ingredient (A) or (B) in “the aqueous liquid in which theingredient (A) is suspended” or in “the aqueous liquid which containsthe molten ingredient (B)” can be preferably from 0.1 to 50 wt. %, morepreferably from 0.5 to 40 wt. % from the standpoint of stability andexternal appearance. The weight ratio of ingredient (A) to ingredient(B) to be used can be preferably in a range of 00.1<(A)/[(A)+(B)]<0.9,more preferably in a range of 0.3<(A)/[(A)+(B)]<0.7 from the standpointof stability and external appearance.

“The aqueous liquid in which the ingredient (A) is suspended” or “theaqueous liquid which contains the molten ingredient (B)” may contain asurfactant as a dispersant. As such a surfactant, an anionic surfactantor amphoteric surfactant can be mentioned.

As anionic surfactants, sulfate-type anionic surfactants, sulfonate-typeanionic surfactants and carboxylate-type anionic surfactant arepreferred. Examples include alkyl sulfates, polyoxyalkylene alkyl ethersulfates, polyoxyalkylene alkenyl ether sulfates, sulfosuccinatealkylene alkylphenyl ether sulfates, and higher fatty acid salts. Amongthese, preferred are polyoxyalkylene alkyl ether sulfates,polyoxyalkylene alkenyl ether sulfates and alkyl sulfates, with thoserepresented by the following formula (1) or (2) being preferred.R¹O(CH₂CH₂O)_(n)SO_(m)M  (1)R²OSO₃M  (2)wherein R¹ represents an alkyl or alkenyl group having a carbon numberof from 10 to 18, R² represents an alkyl group having a carbon number offrom 10 to 18, M represents an alkali metal, alkaline earth metal,ammonium, alkanolamine or basic amino acid, and m stands for the valueof from 1 to 5 on weight average.

As amphoteric surfactants, acetobetaine-type amphoteric surfactants,amidoacetobetaine-type amphoteric surfactants, sulfobetaine-typeamphoteric surfactants, amidosulfobetaine-type amphoteric surfactants,phosphobetaine-type amphoteric surfactants, alkylamine oxides,amidoamine oxides and the like can be mentioned. Among these, fatty acidamidopropyl betaines such as coconut oil fatty acid amidopropyl betaineand lauramidopropyl betaine are preferred.

Two or more of these surfactants may be used in combination. The contentof such a surfactant in “the aqueous liquid in which the ingredient (A)is suspended” or in “the aqueous liquid which contains the molteningredient (B)” can preferably be from 1 to 70 wt. %, more preferablyfrom 5 to 50 wt. %, even more preferably from 7 to 30 wt. %.

In the aqueous liquids, a water-soluble high molecular substance may beincorporated to improve the dispersion stability. As the water-solublehigh molecular substance, a cationic polymer or nonionic polymer ispreferred, with cationized cellulose or cationized guar gum beingpreferred.

The cleansing composition according to the present invention can beproduced by adding the ingredient (B) which has been molten beforehand,or the aqueous liquid which contains the molten ingredient (B), to theaqueous liquid in which the ingredient (A) is suspended, and cooling theresultant mixture to cause the ingredient (B) to deposit.

The aqueous liquid in which the ingredient (A) is suspended can beproduced in accordance with a usual process for the production of pearlysuspensions. Described specifically, the ingredient (A), water and, ifnecessary, a surfactant and/or water-soluble high molecular substanceare mixed, heated, and stirred. The heating temperature can be set abovethe melting point of ingredient (A), preferably at a temperature higherby 10° C. or more of the melting point of ingredient (A). The stirringspeed can preferably be from 10 to 100 rpm, and from the standpoint ofworking efficiency, the stirring time can preferably be from 5 to 60minutes. As a result, the ingredient (A) is molten and the liquid isbrought into an emulsified, dispersed state. With stirring, the liquidis then gradually cooled and is kept at room temperature such that theingredient (A) is caused to deposit.

Ingredient (B) to be added to the suspension of ingredient (A) isrequired to being molten state. The molten ingredient (B) can be addedby itself, or an aqueous liquid in which the molten ingredient (B) iscontained can be added. The aqueous liquid in which the molteningredient (B) is contained can be prepared in a similar manner as inthe above-described ingredient (A). Described specifically, theingredient (B), water and, if necessary, a surfactant and/orwater-soluble high molecular substance are mixed, heated, and stirred.The heating temperature can be set above the melting point of ingredient(B), preferably at a temperature higher by 10° C. or more of the meltingpoint of ingredient (B). The stirring speed can preferably be from 10 to100 rpm, and from the standpoint of working efficiency, the stirringtime can preferably be from 5 to 60 minutes. As a result, the ingredient(B) is molten and the liquid is brought into an emulsified, dispersedstate.

When the molten ingredient (B) or the aqueous liquid containing themolten ingredient (B) is added to the suspension of ingredient (A) andthe resultant mixture is cooled, the ingredient (B) deposits on thesurfaces of the crystals of ingredient (A) so that the cleansingcomposition having pearlescence according to the present invention canbe obtained.

As an alternative, the addition of the molten ingredient (B) or theaqueous liquid which contains the molten ingredient (B) to thesuspension of the ingredient (A) can also be effected by successivelyadding the suspension of ingredient (A) and ingredient (B) or theaqueous liquid which contains the ingredient (B) to an aqueous solutionwhich has been prepared separately to contain an anionic surfactant,amphoteric surfactant, cationic surfactant or the like.

The cleansing composition having pearlescence, which has been preparedas described above, is stably dispersed under acidic condition and isexcellent especially in high-temperature stability, and can be suitablyused especially as a cleansing composition such as a shampoo, body washor facial wash.

The total content of ingredients (A) and (B) in the cleansingcomposition according to the present invention may preferably be from0.3 to 10 wt. %, more preferably from 0.5 to 5 wt. %, even morepreferably from 0.8 to 3 wt. % from the viewpoint of beautifulpearlescence and good stability (especially, stability at hightemperatures).

The cleaning composition according to the present invention can have apH of preferably from 1 to 5, especially from 3 to 4 as measured in theform of a 5 wt. % aqueous solution [20-fold dilute solution (by weight)]at 25° C. For the adjustment of the pH, an organic acid or inorganicacid can be used. Examples of the organic acid include hydroxy acids,monocarboxylic acids, dicarboxylic acids, tricarboxylic acids,polycarboxylic acids, alkyl sulfates, and alkyl phosphates. Examples ofthe hydroxy acid include glycolic acid, lactic acid, oxybutyric acid,glyceric acid, malic acid, and tartaric acid. Examples of themonocarboxylic acid include acetic acid, examples of the dicarboxylicacid include malonic acid, succinic acid, glutamic acid, adipic acid,maleic acid, fumaric acid and phthalic acid, and examples of thetricarboxylic acid include citric acid. Examples of the inorganic acidinclude hydrochloric acid, sulfuric acid, and phosphoric acid. Amongthese, organic acids are preferred, and α-hydroxycarboxylic acids,especially lactic acid and malic acid are superior in providingsleekness, softness, flexibility and manageability to the hair. Thecontent of an organic acid or inorganic acid in the cleansingcomposition according to the present invention can be preferably from0.05 to 10 wt. %, more preferably from 0.1 to 5 wt. %, even morepreferably from 0.5 to 1 wt. %.

In the cleansing composition according to the present invention, asilicone can be incorporated to further improve the conditioningeffects. Examples of the silicone include dimethylpolysiloxane(viscosity: 5 to 2×10⁷ mm²/s), amino-modified silicones,polyether-modified silicones, methylphenylpolysiloxane,fatty-acid-modified silicones, alcohol-modified silicones,alkoxy-modified silicones, epoxy-modified silicones, fluorine-modifiedsilicones, cyclic silicones, and alkyl-modified silicones, withdimethylpolysiloxane being more preferred. The content of the siliconein the cleansing composition according to the present invention canpreferably be from 0.01 to 10 wt. %.

In the cleansing composition according to the present invention, one ormore other conditioning ingredient (s) such as cationic polymers(cationized cellulose, cationized guar gum, and the like) can beincorporated. The content of such other conditioning ingredient(s) inthe cleansing composition according to the present invention canpreferably be from 0.1 to 5 wt. %.

In addition to the above-described ingredients, ingredients which areemployed in ordinary cleansing and cosmetic compositions can also beincorporated in the cleansing composition according to the presentinvention as needed depending upon the purpose of use. Such ingredientscan include humectants such as propylene glycol, glycerin, diethyleneglycol monoethyl ether, sorbitol and panthenol; colorants such as dyesand pigments; viscosity controlling agents such as methylcellulose,polyethylene glycol and ethanol; and further, plant extracts,preservatives, antifungal and/or antimicrobial agents, chelating agents,vitamins, anti-inflammatories, fragrances, ultraviolet absorbers,antioxidants, and the like.

The cleansing composition according to the present invention is veryuseful as a hair cleansing composition, skin cleansing composition orthe like.

EXAMPLES Example 1

(1) Preparation of a Suspension of the Ingredient (A)

Water (10 g), ethylene glycol dialkylate [ingredient (A): acyl group(carbon number: 18) ester, 50 wt. %; acyl group (carbon number: 16)ester, 50 wt. %; 20 g], a 30 wt. % aqueous solution (67 g) of sodiumpolyoxyethylene lauryl sulfate and coconut oil fatty acidmonoethanolamide (3 g) were heated to 80° C. and then stirred for about1 hour to give a homogeneously-emulsified dispersion. Under gentlestirring, the dispersion was then allowed to gradually cool down to roomtemperature to give a solid suspension having an average particle sizeof not greater than 1,000 μm.

(2) Production of a Cleansing Composition (Shampoo) Having PearlescenceAccording to the Present Invention

Water (40.5 g), a 30 wt. % aqueous solution (50 g) of sodiumpolyoxyethylene lauryl sulfate, coconut oil fatty acid monoethanolamide(2 g) and cationized cellulose (0.5 g) were heated to 80° C. and thenstirred for about 1 hour to give a homogeneously-emulsified dispersion.Under gentle stirring, the dispersion was then allowed to gradually cooldown. When the temperature dropped to around 57° C., the suspension (5g) of the ingredient (A) obtained in the above-described procedure (1)was added. Added next at 56° C. was a melt (1 g) of ethylene glycoldialkylate heated at about 80° C. [ingredient (B): acyl group (carbonnumber: 18) ester, 95 wt. %; acyl group (carbon number: 16) ester, 5 wt.%]. The resultant mixture was allowed to gradually cool down to roomtemperature to give a shampoo according to the present invention.Subsequently, the pH of the composition [20-fold dilute solution (byweight)] was adjusted to 3.8 by using lactic acid (1 g) and hydrochloricacid or sodium hydroxide (q.s.).

Example 2

A shampoo according to the present invention [pH of 20-fold dilutesolution (by weight): 3.8] was obtained in a similar manner as in theprocedure (2) of Example 1 except that the amounts of water and thesuspension of the ingredient (A) were changed to 38.5 g and 7 g,respectively, and in place of the cationized cellulose, the same amountof “MERQUAT 550” (product of Calgon Corp.) was used.

Example 3

A shampoo according to the present invention [pH of 20-fold dilutesolution (by weight): 3.8] was obtained in a similar manner as in theprocedure (2) of Example 1 except that the amounts of water, thesuspension of the ingredient (A) and the melt of the ingredient (B) werechanged to 41.5 g, 3 g and 2 g, respectively, and in place of thecationized cellulose, the same amount of cationized guar gum was used.

Example 4

A shampoo according to the present invention [pH of 20-fold dilutesolution (by weight): 3.8] was obtained in a similar manner as in theprocedure (2) of Example 1 except that the amount of water was changedto 39.5 g, and in place of the melt of the ingredient (B), a mixture(1:1 by weight; 2 g) of the ingredient (B) and propylene glycol whichhad been heated to 80° C. was used.

Comparative Example 1

Water (41 g), a 30 wt. % aqueous solution (46.65 g) of sodiumpolyoxyethylene lauryl sulfate, coconut oil fatty acid monoethanolamide(1.85 g) and cationized cellulose (0.5 g) were heated to 80° C. and thenstirred for about 1 hour to give a homogeneous liquid. Under gentlestirring, the liquid was then allowed to gradually cool down. When thetemperature dropped to around 57° C., the suspension (10 g) of theingredient (A) obtained in the procedure (1) of Example 1 was added. Theresultant mixture was then allowed to gradually cool down to roomtemperature to give a shampoo.

Test 1

The shampoos obtained in Examples 1-4 and Comparative Example 1 wereranked for the appearance, the touching feel of the foam and thestability under acidic condition in accordance with the followingstandards. The results are shown in Table 1.

Ranking Standards

External Appearance

The external appearance of each shampoo was visually observed, and wasranked in accordance with the following standard.

A: Strongly pearly appearance.

B: Lightly pearly appearance.

C: No pearly appearance.

Touching Feel of the Foam

Adequate amounts of each shampoo and water were taken on the hands andwere then foamed. A touching feel at that time was ranked in accordancewith the following standard.

A: Soft and silky.

B: Coarse and collapsed feel.

Stability Under Acidic Condition

Each shampoo was stored while maintaining its temperature at 50° C. Aperiod of time during which the stability (pearly appearance) of thesystem was maintained was determined.

A: Remained stable for 1 month or longer.

B: Stable for 20 days.

C: Pearly appearance disappeared in less than 20 days. TABLE 1 Comp.Examples Ex. 1 2 3 4 1 External appearance A A A A A Touching feel ofthe foam A A A A A Stability under acidic condition A A A A B

1. A process for preparing a cleansing composition having pearlescence,which comprises: mixing an aqueous liquid in which an ingredient (A) issuspended with an ingredient (B), which is molten prior to mixing, or anaqueous liquid in which said molten ingredient (B) is contained; andcooling the resultant mixture to cause said ingredient (B) to deposit,wherein: said ingredient (A) is at least one ester selected from thegroup consisting of an ethylene glycol monoalkylate and ethylene glycoldialkylate, which may have a distribution in the number of carbon atomsin its constituent fatty acids, with the proviso that fatty acids havingcarbon numbers of 18 and greater account for less than 70 wt. % of allof said constituent fatty acids; and said ingredient (B) is at least oneester selected from the group consisting of an ethylene glycolmonoalkylate and ethylene glycol dialkylate, which may have adistribution in the number of carbon atoms in its constituent fattyacids, with the proviso that fatty acids having carbon numbers of 18 andgreater account for 70 wt. % or more of all of said constituent fattyacids.
 2. The process according to claim 1, wherein the aqueous liquidin which said ingredient (A) is suspended and/or said aqueous liquid inwhich said molten ingredient (B) is contained further comprises asurfactant.
 3. A cleansing composition having pearlescence, which isobtained by a method comprising: adding an ingredient (B), which ismolten prior to mixing, or an aqueous liquid in which said molteningredient (B) is contained, to an aqueous liquid in which an ingredient(A) is suspended; and cooling the resultant mixture to cause saidingredient (B) to deposit, wherein: said ingredient (A) is at least oneester selected from the group consisting of an ethylene glycolmonoalkylate and ethylene glycol dialkylate, which may have adistribution in the number of carbon atoms in its constituent fatty withthe proviso that fatty acids having carbon numbers of 18 and greateraccount for less than 70 wt. % of all of said constituent fatty acids;and said ingredient (B) is at least one ester selected from the groupconsisting of an ethylene glycol monoalkylate and ethylene glycoldialkylate, which may have a distribution in the number of carbon atomsin its constituent fatty acids with the proviso that fatty acids havingcarbon numbers of 18 and greater account for 70 wt. % or more of all ofsaid constituent fatty acids.
 4. The cleansing composition according toclaim 3, wherein said aqueous liquid in which said ingredient (A) issuspended and/or said aqueous liquid in which said molten ingredient (B)is contained further comprises a surfactant.